How does a ferrofluid audio (sound) visualizer work?

First, you'll need a ferrofluid display bottle

Then, you need an audio visualizer.

which can either be voice-activated or have an audio line-in.
This site only has voice-activated ones, the audio line-in ones are obsolete, so try asking if you need one.

Once, again you need an electromagnet

Finally, you will need to assemble them together and energize them.

How much voltage and current you end up needing to use depends on the properties of the solenoid.
The electromagnet for this combo is 12V. but I am using a 5V USB power adapter. Here I need to use a USB boost cable to convert the 5V voltage to 12V output.

Having said that, how do they work?

——The visualizer controls the switching and strength of the electromagnet by picking up external sounds, This will drive the ferrofluid to dance.

——Simply put, it means you can clap, bang on the table, talk and sing, make any business. The ferrofluid then you can dance.

——If you first ferrofluid rhythmic dance, then you can play a piece of music on your cell phone, or MP3, everything that comes through the speakers.

——It's that simple.